Operating mechanism for, electric furnaces



J. H. GRAY.

OPERATING MECHANISM FOR ELECTRIC FURNACES.

APPLICATION FILED APR. l2. I919.

1,376,758. Patentd May 3, 1921.-

4 SHEETS-SPIKE! i.

INVENTOR Ja m esH Gm;

M ATTORNEY J GRAY.

i';;-";!'lNG MECHANISM FOR ELECTRIC FURNACES. APPLICATION mzo APR. 12-. I919.

P d M y 3,1921.

4 SHEETS-SHEET 2.

INVENTOR 1. H. GRAY. I OPERATING MECHANISM FOR ELECTRIC FURNACES. APPLICATION FILED APR. 12. l9l9- 1,376 758. Patented M y-3, 1921 INVENTOR Jiimes'fl Gray Y eral use of a three-phase current, these UNITED STATES Parana tries..-

JAMES H. GRAY, or new Yon N. Y.

Specification of Letters Patent.

Patented May 3, 19211.

Application filed April 12, 1919. Serial No. 289,567.

To all whom it may concern:

Be it known that 1, James H. GRAY, citizen of theUnited States, residing in the city,-county, and State of New York, have invented certain new and useful Improvements in Operating Mechanism. for Electric Furnaces, of which the following is a specification,

Electric furnaces of the type used in treating steel and iron are generally arranged to tilt from an upright 'to an inclined position for emptying the furnace, withdrawingslag and other purposes. On account of the genfurnaces usually have three electrodes. The electrodes are quite heavy, each weighing over two tons in the largerfurnaces. are arranged to be lowered or raised for the purpose of striking or breaking the arc,and during the operation of melting or treating steel they are moved upward and downward short distances for the purpose of regulating the amount of current flowing by increasing or decreasing the length of the arc. Usually they are supported and lifted by-cranes mounted on the furnace and movable upward and downward, or by cables passing up over sheaves and leading to winding motors mounted on the furnace. Such arr; ngements put an excess weight on the shell of the furnace and require heavy auxiliary supporting members. Also the heat and fumes coming from the furnace are destructive to the motor and to the gearing generally used for reducing tl speed between the motor and the electrodgs.

My invention provides a mechanism for operatin the electrodes by which. the motor or 0 her source'of power can be fixed and mounted on a stationary structure so as to a mid the disadvantages of the old sytle mechanism. At the same time the electrodes may be held in fixed position with reference to the furnace while the latter is being tilted. p

The accompanying drawings illustrate different embodiments of the invention.

Figure 1 is a plan; Fig. 2 is aside elevation, guide sheaves;

They

' beams 7 omitting certain Fig. 3 is .1 section on theline in nr a of Fig. 2;

Flgs. a, 5 and 6 are diagrams showing separately,the three operating cables of the pretrating still another arrangement of sheavcs.

Referring first to Figs. 1 to 6, the furnace 1 is provided with three electrodes 2 each of which is clamped in a holder in the end of a bus bar 8 connected by flexible cables i with a transformer 5 from which the current is conveyed to the electrodes. Qolumns 6 are mounted on the side of the furnace and carry ap their upper ends longitudinal on which is supported a cross-beam 8 extending over the side of the furnace. On the beams 7 and 8 there are supported pairs of sheavesf) and single sheaves 1t) 10-- cated above the electrodes and the bus bars. Each electrode is supported by cables 11 attached to the ends of the bus bars alongside the electrode. running up and over the sheaves 9 and thence to blocks 12.where their ends are fastened. Cables 13 areattached to the bus bars near their innercnds' and pass up and over the guide pulleys 10 and thence to the blocks 12 where their ends are also fastened. The blocks 12 thus serve as points of attachment for theimeans for supporting and raising or lowering the bus bars and electrodes. The furnace has a discharging spout 14:, Fig. 1, at one side and a rear chargii'ig door 15.. with additional charging doors at the sides if desired,- and is arranged to rock or turn about an axis indicated by the dotted line 16, Fig. 2, and the point 16, Fig. The angle 17, Fig. 3, indicates the extent to which the furnace is turned from an upright to a tilted position.

The blocks 12 are held in the bight of certain operating cables in such a way that the tilting of the furnace neither raises nor shortened by suitable" motors to lower o V the furnace.

lowers the electrodes. at the same time these operating cables can be lengthened o raise the electrodes during-the operation 0 The blocks 12 are provided with guide pulleys 18, 19 and 20 identical with each other but differently numbered to better explain their operation. The crossb'earn 8 has at its inner end a shortupright 21 onwhich is pivotally supported a block 22 carrying a set of three pulleys at each of its opposite ends. Three motors 23 (Fig. 3) are arranged to drive in any usual or suitable way drums 2 1. The motors with their gearing and drums are mounted one Wall 25 which houses the transformer. From the first druin a cable passes up and over a guide pulley 27 fixed on the supporting wall 25, thence around a pulley 28 on one end of the block around pulley 20 of the first electrode, and back to a pulley 29 on the same axis with the pulley 28, and around this pulley and thence to a tired sup port 30 mounted also on'the supportin5; wal 25, its end being: fixed to the support 30. The next operating cable 31 passes oyeh' a fixed guide pulley 32 thence over. a pulley 33 between the pulleys 28 and 29, around this and to and. around the pulley 19 which supports the second electrode, to a pulley 34: at the opposite side of the block 22 and around this and to the fixed support 30, where its end is fastened. The third operating cable 35 passes over a guide pulley 36 thence to a pulley 37 on the pivoted block, to the pulley 18 which supports the third electrode, back to a pulley 38 on the same axis with the pulley 37 and thence to the fixed support 30 where its end is fastened. Thus, as will. appear more clearly in -l, and two of the pulleys on one end of the pivoted block 22, namely 28 and 29 carry the operating cable 26 to the corn pondingly located pulley 20, two pulleys 3i and 33 at the. opposite end of the pivoted block C21"l" *\l$ the operating' cable to the opp pulley 1.8 for the third eecti an (i puileys '33 and 34 at opposite ends of the pivoted block carrying the operating cable 31 for the intermediate supporting pulley 19. Thus the strain on the two ends of the pivoted block is balanced and the operating cables do not introduce any tendency to turn this pivoted block during the working of the fun nace.

angle 17, Fig. 3, the cross-beam 8 is carried with it and moves to the position shown in dotted lines. The operating cables passing through this block'tend to hold it always in the parallel lines extending from the fixed guide pulleys 27, 32 and 36, to the points of attachment of the cable ends to the fixed support 30. As the furnace turns the pivotal center of the block 22 will describe an are supporting lVhen the furnace is tilted through the .Qghtly above the line of parallel Tl e angle of the operating caz-igh the block is so arranged idinal axis of the block, as

the furnace is tilted, will reach a position at 7F) right angles tot-he vertical axis of the fun hues and then, as thetilting movement con tinues, will. take angular position iii-the op posite direction to that which it had, at the beginning of the movement. .i referably the directionIo; the cables is norin'alto the niedian line 39 between the two sides of the angle 17; so that in the tilted position the center of the block 22 will be as far to one side of this line as it is to the other side of, 30

this line in the starting position, and so that the two extreme positions of the pivotal center of the block will be on a line parallel with the cab es passing through it. For example, if the liu'nace be designed to tilt-to 35 an a le of 40 degrees irom the vertical, then l5 stands at one-hall this angle with al. and the operating cables from the the this amount or an angle of 20 degrees from a tilt? hoi.

mental, which is the same thing; as saying; tha t the direction of the cables must be at a right angle to the line 3.) which bisects the angle 17. Any departure from this rule will mean len thenin oi the iortions ll ithin a small limit, such a stationary and hold the drums 2i stationary.

The cables are wound around the drums and carry counter-weights 4.0 at their lower ends'which are normally a determined distance above the floor ll or other supportprovided for them.

electrode holder, bus bar and flexible cable, plus the average weight of the electrode; or it be heavier or lighter than the sum liach counter-weight may have-the weight of the cm'respondlng of such weights. If it is lighter than the opposing force it will. still put sufiicient tension on the cable to cause it to bind on the drum, thus locking the cable when the drum is locked or lifting the electrode when the drum is turned in proper direction by the motor. The length of the cable 26. or the distance of the counter-weight above the floor 41 is such that when the electrode holder reaches the desired upper end of its stroke, the counter-weight'will rest on the floor. This will loosen the cable on the drum and although the motor may continue to operate, the electrode holder will not be moved beyond its normal travel,--a movement which would result in breaking the cable or some other part of the furnace. If

the counter-weight be considerably heavier" thannthe opposing forces, nevertheless the weight of the electrode holderand connected parts will be sufficient "to give the cable the necessary tension to cause 'it o bind on the drum, so that there will be no movement except as the drum is rotated, and the tilrning of the drum in the proper direction will lift the weight and allow the electrode holder.

to descend. The turning of the drum in the opposite direction of course"lifts the electrode holder and lowers the counter-weight until itstrikes the floor or other rest. It will")e-see1i therefore that the function of the c 'unter-weight is largely that of a takeup for the tension on the cable, with alimited movement which releases the tension at the desired point.

' This arrangement has advantages over those-previously used, especiall in the mat ter of safety. The motors are sually actuated by the electric current which is auto--' ing to loosen the cables (to permit the elec- 4:6 and 47 and the bight ofit over pulley l8.

trodes to descend) which, after being unwound to their limit, and having their ends fastened to thewinding drum, have been wound up in the other direction, lifting the electrode and breaking the mechanism.'

Such an accident is avoided by my arrangement of cables and weights because if the electrode rests on the scrap or on the bottom of the furnace the tension in the cables is removed by a continued operation of the motor in the lowering direction, and they no longer emu on the drum; so that the motors may continue to operate without effect.

The arrangement in Figs. 7 and 8 dilfers merely in the arrangement .of the pulleys in the pivoted block 22, and in the arrangement of the cables passing through it. Here the cable 26 runs over pulleys 42 and 4:3 in line with each other on opposite ends of the block 22, the bight of the cable between the pulleys 4:2 and 4:3 passing to the ele ctrode pulley 20. The cable 31 passes over pulleys 4A and ii) in line with each other at opposite ends of the pivoted block 22, the eight of the cable passing over the pulley 19 Similarly the cable 35 passes over pulleys The mode of operation and the functioning of the parts similar to those of Figs 1 t0 6.

According to Fig. 9 a pivot block 48 is used which differs slightly from that .of the previous figures. It-is mounted on trunnlons in a pair of upright posts 8 (see Fig.

10) and is provided with three pairs of pulleys, onepair at the-center and one pair at each end.. The first cable 26 willpass around the pulley 49 to and around the pulley 20 and thence to and around the larger pulley-'50 which is loosely mounted on the same axis with'the pulley 49. The cable 31 I will pass in a similar wayaround the two intermediate pulleys of the pivoted block, and around the intermediate electrode supporting pulley 19. And the third cable 35 will pass around, the two pulleys at the opposite end of the pivoted.block and around the pulley 18. The pulleys within the block 48 are made of different sizes so as to cause the cables to clear each other as they pass behind through the rear portion of the block. 851- In all the foregoing designs, where the cables pass in a straight line from the sup-' porting pulleys at the right to the pivoted block and from said block to the fixed ends at the left, there is a slight lengthening of 0 the portion of the cable in question as the". block swings away from its supporting position, until it reaches its middle position, after which the cable is shortened and becomes at the end of the movement, of it's initial length; these lengths of cable being bent out of their original straight lines from ,theguide pulleys to the fixed ends. The departure is greatest at the middle point of thearc 17*, Fig." 8. The positions of the pulleys 27, 32 and 36 and ofthe fixed ends of the cables may be soarranged that inthe upright position of the furnace the cables will be, not in a straight line as shown, but in a bent line; the block QQ'lIIfltS starting position being depressed below a straight line by distances equal t6 one-half the effect caused by the arc; so that" in the" center point of the tilting movement it will be equally offset on the opposite side' of the straight line. Thus thevariationfroin 'a I straight line will be only one-half that-o'ccasioned with the arrangement of Fig. 8 where the cables stand in a straight line at the beginning and end of the movement. This offset movement pulls the cable and lifts the electrode, no matter whether the departure from a straight line be upward or downward. Such an arrangement therefore would result-in first lowering the electrodes by a trifling distance and then raising them to the starting position at the end of the 'movement. Total movement of an electrode in either case is very trifling, about onetenth of an inch in the arrangement ofFigs. .125 3 and 8 and about one'twentieth ofan inch in the alternative arrangement. It is desily able to have this movement very slight-be cause when the furnace is tilted from its vertical position there is considerable friction involved in any movement of the electrode with relation to the furnace. A movement of one-twentieth or even one-tenth of an inch is not enough to be seriously objectionable, but the cables may be so arranged that there will not be any movement, even theoretically.

In the construction of Figs. 11 to 13 these cables extend always in the same are about the center 16, sothat as the block 51 swings from an upright to an angular position the cables remain unchanged in length. A rack or support 52 is attached to the wall 25 of the transformer room or some other support.

It is in the form of an. arc struck from the center 16 about which the furnace tilts.

' It underlies the several operating cables 26,

31 and 35; The block, 51 is fixed on the crossbeam 8 of the furnace and carries pulleys 53 from the electrode supporting pulley 20; pulleys 55 and 56 over which the cable 31 passes to and from the electrode supporting pulley 19; and pulleys 57 and 58 over which the operating cable 26 passes. around the electrode supporting pulley 18. The pulleys 53 and 58 are arranged in pairs on separate blocks as shown or various other styles of mounting may be used for them.

Though I have described with great particularity of detail certain embodiments of my invention, yetj it is not to be understood therefrom that the invention is restricted to the particular embodiments disclosed. Various modificationsthereof in detail and in the arrangement of the parts may be made by those skilled in the art without departure from the invention as defined in the following claims.

What I claim is:-

1. The combination with a tilting .electric furnace of mechanism for adjusting electrodes in said furnace, said mechanism comprising aj'fmotor mounted on a stationary support and transmission. means between the motor and the electrodes adapted to hold the latter in substantially the same position with reference to the furnace when the furnace is tilted as when it is upright.

2. The combination with a tilting electric furnace of mechanism for adjusting electrodesin said furnace, said mechanism comprising a motor mounted on a stationary support, and lifting cables from said motor to theelectrodes, said cables being of substantially the same effective length in the tilted position of the furnace and in its upright position.

3. The combination with a tilting electric furnace of mechanism for adjusting elec trodes in said furnace, said mechanism comthe motor to a fixed point and engaging nfitheir bight electrode supports 4. The combination with a tilting electric furnaceof mechanism for adjusting eleca trodes in. said furnace, said'mechanism. comprising a motor. mounted on a stationary support and operating cables extending from the motor to a fixed point and engaging in their bight electrode supports, the direction of said operating cables being such that their length is substantially unchanged as the furnace passes from an upright to a tilted position.

5. The combinationwith a-tilting electric furnace of electrode-adjusting mechanism for said furnace, said mechanism comprising a motor mounted independently of the furnace and transmission means between the motor and electrodes, said motor and tIflnSIIllS' sion means being arranged to hold the elec trodes in substantially the same position with and 54 over which the cable 35 passes to and reference to the furnace when the furnace is tilted as when it is upright.

6. The combination with a tilting electric a motor mounted independently of the furnace and transmlssion means between the.

motor and electrodes, said motor and transmission means being arranged to hold the electrodes in substantially the same position with reference to the furnace throughout the tilting movement of the furnace.

7 The combination with a' tilting electric furnace of mechanism for adjusting elec trodes in said furnace, said mechanism comprising a motor mounted on a stationary support and transmission means between the motor and the electrodes adapted to hold the latter-in substantially the same position with reference to the furnace throughout the tilt ing movement of the furnace.

8. The combination with a tilting electric furnace of mechanism for adjusting electrodes in said furnace, saidmechanism comprising a motor mounted on a stationary support and operating cables extending from the motor to a fixed point and engaging in the angle through which the furnace tilts.

9. The combination with a tilting electric furnace of mechanism for adjusting electrodes in said furnace, said mechanism comprising motors mounted on a stationary support, drums operated by said motors and operating cables passing from the electrodes to and around said drums and carrying at their ends weights adapted to maintain them in frictional engagement with said drums.

' 10. An electric furnace having adjustable electrodes, motors, drums operated thereby, automatic regulators for said motors 'and cables for operating said electrodes, said ca bles passing to and around said'drums, and weights on the ends of sald cables adapted to maintain them in frictional engagement tain them in frictional engagement with said with said drums. drums, and supports for said weights limit- 10 11. An electric furnace having adjustable ing the extent of movement of the cable electrodes, motors, drums operated thereby, through which the drum will frictionally 5 automatic regulators for said motors and caengage it to lift the electrode.

bles for operating said electrodes, said cables In Witness whereof I have hereunto signed passing to and around said drums, weights my name.

011 the ends of said cables adapted to maIn- JAMES H. GRAY. 

